The most common dosage forms currently employed for oral administration of active substances are tablets and capsules. However, in recent years awareness of the drawbacks of using these dosage forms has increased. Thus, tablets and capsules are generally less suitable for administering large dosages of an active substance as large tablets or capsules are difficult to ingest, or the large dosages necessitate the administration of several tablets or capsules at a time, resulting in impaired patient compliance. Furthermore, patents often have to take several different tablets or capsules containing different active substances either at a time or at specific intervals during the day. This also leads to reduced patient compliance.
Active substances may alternatively be formulated as powders or granules to be admixed with a liquid in a container such as a glass before administration, thereby overcoming the difficulties involved in administering large dosages of an active substance in tablet or capsule form. However, with such a formulation other problems arise, especially when the active substance in question is not dissolved in the liquid, but is present in particulate form. In such cases, the particles tend to sink to the bottom of the glass and stay there even when the contents of the glass are stirred before the glass is upended for ingestion of the liquid or to adhere to the sides of the glass when the liquid is ingested. In this way a certain amount of the active substance will remain in the glass giving rise to an unacceptable variation in the dosage of the active substance actually ingested by those to whom it is administered in this form. Furthermore, such granules or particles often have an unpleasant feel in the mouth as they typically have an irregular shape which makes them feel gritty, and they also tend to adhere to oral mucosa after the liquid carrier has been washed down. Such a dosage form therefore also tends to lead to reduced patient compliance.
Chewable tablets are not a viable alternative in most cases as they may be difficult to masticate especially for older people and young children and, importantly, as most drugs have an extremely unpleasant taste. If the active substance is formulated in controlled-release form as particles containing the active substance coated with a controlled-release coating, it cannot be compounded into chewable tablets as this would destroy the controlled-release effect.
Therefore, there is a need of a formulation of active substances permitting the administration of large dosages at a time and making it easy to ingest the dosage of the active substance, and which furthermore provides an easy way of administering several active substances in the same dosage.